The present invention relates to a flightless rock auger suspended from a derrick and powered by a shaft linked to a power source for removing plugs of rocks from post holes.
Poles for power lines and communication purposes are required to be vertical and arranged in straight lines. The poles may be planted in positions which are relatively inaccessible. A crane may be utilized for providing an outreaching means. Typically a digger derrick consists of a telescopic mobile crane from which is suspended a torque head. A flighted auger is suspended from the torque head and utilized for drilling in soil containing loose rock. The digger derrick is advantageous for extending the auger to the desired location. The auger may be stowed in a fixed position or extended in a telescoping position as needed to reach the desired location for drilling the hole.
Depending on the nature of the digging device, its digging element, or auger, torque head or hydraulic pressure is typically exerted on the digging element via air or oil hydraulic pressure exerted by the crane or cylinder in cooperative engagement therewith for forcing the digging element into the earth.
Although the conventional flighted auger is adequate for drilling through soil, or even soil with loose rock, the drilling operation must be suspended upon hitting a large rock or rock ledge because the flighted auger cannot penetrate the hard rock surface. The flighted auger is then lifted out of the hole and conventional methods of removing the obstruction with a steel shaft, crowbar, or explosive charge are used to break-up the hard rock. The flighted auger is then lowered back into the hole to remove the loose rock and soil.
A considerable amount of time is lost during the rock break-up and removal procedure. Moreover, an effort is continually being made to minimize work with explosives due to the liability of injury to workers and/or damage to residents or businesses in the area which may be in the area of the blasting zone and susceptible to rock or vibration damage.
The present invention provides a flightless rock auger having a cylindrical hollow cutting head and a plurality of teeth extending from the lower periphery thereof. A support member extends across a portion of the cylindrical hollow cutting head providing a means for cooperative engagement with a shaft extending outwardly therefrom. A quick disconnect coupling is disposed upon the distal end of the shaft.
A preferred embodiment of the flightless rock auger system for use with a drilling rig includes a flightless rock auger having a cylindrical hollow cutting head with a plurality of cutting teeth extending from the bottom edge of the cutting head. A support member extends across a portion of the cylindrical hollow cutting head providing a means for cooperative engagement with a vertical drive shaft extending outwardly therefrom. A quick disconnect coupling is disposed upon the distal end of the shaft. A means for rotating the drive shaft such as a mechanical or fluid drive may also power the hydraulic mechanism for lifting and lowering the drive shaft which utilizes its own weight for exertion of downward pressure onto the hard substrate.
A method of removing hard substrate from a posthole, using a flightless rock auger with a drilling rig simply requires the attaching a flightless rock auger having a cylindrical hollow cutting head and a plurality of cutting teeth extending from the bottom edge of the cutting head. A support member extends across a portion of the cylindrical hollow cutting head providing a means for cooperative engagement with a vertical drive shaft extending outwardly therefrom. A quick disconnect coupling is disposed upon the distal end of the shaft to means for rotating the drive shaft. The flightless rock auger is lowered into a posthole containing a hard substrate and resting the flightless rock auger onto the hard substrate. The auger is rotated at a very low rpm for from about 3 rpm to about 10 rpm forming a plug of hard substrate inside of the cylindrical body of the flightless rock auger. Lifting the flightless rock auger and the plug from the posthole is simple and the plug of the hard substrate is removed from the flightless rock auger head. The flighted auger is then substituted for removing soil from the posthole.
Accordingly, it is a principal object of the present invention to provide a flightless auger device for digging through hard rock.
It is another object of the present invention to provide an flightless auger which is capable of drilling through rock and forming a plug removable from the flightless auger.
It is another object of the present invention to provide a flightless auger utilizing an attachment means which is interchangeable with the attachment means typically used with conventional flighted augers for drilling operations.
It is therefore another object of the present invention to design a flightless auger for use at very low revolutions per minute (rpm) to maximize safely and prevent damage to the equipment.
It is an object of the present invention to provide an adapter extending from a shaft for use with a torque head of a drilling derrick.
Another object is to provide a flightless auger having teeth extending outward at a forward angle.
It is another object to provide a flightless auger having a drill head portion utilizing an end diameter of greater diameter than the plug receiving inner diameter.
It is yet another object of the present invention to utilize a plurality of diagonal ribs to minimize suction between the exterior of the drilling head and the walls of the drilled hole.
It is yet another object of the present invention to provide an access port in the top end of the drilling head for removal of the rock plug formed therein.